Simplify the following expression: $k = \dfrac{-2z + 12}{z + 3} + \dfrac{6z - 7}{z + 3}$
Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{-2z + 12 + 6z - 7}{z + 3}$ Combine like terms: $k = \dfrac{4z + 5}{z + 3}$